Taxonomy virus Flashcards
virus are grouped in ?
families
virus are given what to name them?
- Genus name
- Species name
classification of virus is based on what ?
- Nature of the host
- Type of disease caused
- Life cycle
- Naked or enveloped
- Type of nucleic acids and strandedness
What’s the baltimore classficiation scheme?
the type of genome , kind of genome will dictate the replication mechanism
There are two type of RNA genomes
- Plus configuration
- Minus configuration
What’s the plus configuration of RNA genomes?
It’s the same strand of dna and can be translated directly
What’s the minus configuration of RNA genomes?
complementary in base sequence to viral mRNA (needs to be transcribed into plus strand before it can be translated
Life cycle of viruses ,first step?
Adsorption
What’s adsorption ?
attachment - virus - specific receptors- surface of the cell.
plants viruses are usually introduced into the host by ?
insect vectors or following mechanical damage
life cycle of viruses,second step?
Penetration,virus genome enters the cell
in envelopped and naked viruses what enters the cell ?
complete virion may enter the cell
In envelopped virus, the envelope may?
be left at the cell surface such that only the nucleopsid enters the cell
In naked viruses?
the capsid may be left at the surface(everything left at the surface)
Uncoating?
removal of the envelope and/or the capsid by host enzymes,sometimes within lysosomes(in eukaryotes)
direct penetration?
naked virus,everything is left at the surface
In membrane fusion ? (enveloped viruses)
the envelope is left at surface
Who does endocytosis to enter
Most enveloped viruses of eukaryotes (they use viropexis)
What’s viropexis?
Everything gets in (in a second envelope)
What happens with the second envelope that goes in ?
viruses are then delivered to lysosomes which degrade the capsid and the nucleic acid is release into the cytoplasm
Life cycle, third step?
replication of the nucleic acid transcription and protein synthesis
life cycle,fourth step?
Maturation, assembly of virus components,nucleic acid,nucleocapsid and acessory proteins to form new virions
How quick happens the assembly?
spontaneous (occurs by itself)
LIfe cycle, fifth step?
release,matura virions exit the host cell by means of budding or by causin lysis of the cell
When the plant viruses exit it’s transmitted by?
by means of vector
2 importante période dans le virus replication?
- Latent period
- Release(Rise period)
Latent period diviser en deux ?
- Eclipse
- Maturation
What’s Eclipse?
time necessary for the host cells to replicate the viral genome and to synthesize the viral component
What’s maturation ?
time needed for the different components to be assembled
What happens during release?
Virions are detected outside the cell
virions detected outside?
il vont les detecter et donc vont liberer les siens
Apres qu’il est détecté des virions dehors ils font quoi?
Lysis: virus-encoded proteins damage the cytoplasmic membrane”
ds les bacterie c quoi qui cause lysis ?
a virus encoded protein destroys the peptidoglycan layer
aussi peuvent etre liberer par ?
Budding (enveloped virus)
the number of virions released?
burst size
Burst size varies ?
according to the virus,host cell
Tout ce processus prend combien de temps pour une bacterial virus?
20-60 min
Tout ce processus prend combien de temps pour un animal virus ?
8-40h
budding the enveloppe comes from?
the cytoplasmic membrane or the nuclear membrane
